Senior Software Engineer, Backend

At Union, we are solving one of the hardest challenges in AI infrastructure today: enabling high-velocity iteration while maintaining seamless production-readiness for AI workloads at scale.

Flyte, the open-source project we steward, has emerged as the modern standard for data and AI orchestration, and is trusted by leading technology organizations including LinkedIn, Stripe, and Wayve to run millions of mission-critical workflows on the platform. These workflows comprise data preparation, model training, and scaled inference spanning thousands of GPUs, all major clouds, and on-premise infrastructure.

We have a technical founding team who created Flyte while at Lyft, a deep bench of infrastructure experts from top companies, and have raised from top investors like NEA and Nava Ventures.

About the Role

We're looking for a Senior Software Engineer to join our backend team and help build the infrastructure that powers AI workloads at scale. You'll design and implement core services in Go, work across multiple cloud environments, and collaborate with customers and internal teams to deliver reliable, low-latency systems.

This role is ideal for someone who enjoys solving hard distributed systems problems, cares deeply about performance, and wants to work at the intersection of cloud infrastructure and machine learning.

What You'll Do

• Design, build, and operate backend services in Go that handle high-throughput, latency-sensitive workloads.

• Optimize system performance across compute, memory, and network dimensions—identifying bottlenecks and implementing measurable improvements

• Build and maintain integrations with AWS, GCP, and Azure, abstracting cloud-specific complexity behind clean interfaces.

• Architect systems that run reliably across multiple cloud providers, handling the nuances of each platform.

• Collaborate with ML engineers and platform teams to understand workload characteristics and design systems that meet their needs.

• Participate in on-call rotations and incident response, continuously improving system reliability.

• Influence technical direction through design documents, code reviews, and mentorship.

What We're Looking For

• 5+ years of experience building production backend systems, with strong proficiency in Go.

• Demonstrated experience designing and operating large-scale distributed systems (high availability, fault tolerance, horizontal scaling).

• Deep understanding of performance optimization—you can profile code, interpret flame graphs, and reason about latency at the p99 level.

• Significant experience with multiple major cloud providers (AWS, GCP, Azure), including compute, networking, and IAM.

• Familiarity with Kubernetes, container orchestration, and cloud-native patterns.

• Strong communication skills and a collaborative approach to problem-solving.

• If in the Seattle/Bellevue area, you will be expected to be in-office, in a hybrid schedule.

• This role is not eligible for employment visa sponsorship. Applicants must be authorized to work in the United States. H-1B transfers will undergo a case-by-case review.

Nice to Have

• Experience with Python and/or Rust for SDK or tooling development.

• Experience building infrastructure for ML/AI workloads (training, inference, data pipelines).

• Background in systems programming, networking, or storage.

• Contributions to open-source projects.

• Experience with Terraform, Pulumi, or other infrastructure-as-code tools.

Benefits & Belonging

At Union.ai we know that employees who feel their best can build amazing things and we are proud to offer best in class benefits that will continually evolve and grow as the needs of our employees do. Benefits may vary based on country.

• Excellent medical - We pay 100% of your premiums and 90% for your dependents

• Generous dental and vision plans- We pay 90% of the premiums for you and your dependents

• Meaningful equity in the form of options – all employees are owners here

• Unlimited time off + 12 company holidays 

• 401K match - Union.ai matches 100% of contributions up to the first 3%, and 50% up to 5%

• 12 weeks paid parental leave for primary and secondary caregivers

• Flexible work schedule (some restrictions apply)

• For in office employees: Lunch provided onsite and well stocked kitchen with snacks and drinks.

We believe that our differences are what bring us together to achieve truly special outcomes. We strive to be inclusive and focus on building teams that embody that quality too. Union.ai is an equal-opportunity employer and we encourage you to apply, even if your experience doesn’t align exactly with our job description.